Malcolm is working with the steganalysis expert at the local police department. They are trying to break a message they found on a suspect's computer. The steganalysis expert says they are going to try a known cover attack. How is a known cover attack executed? a. It's used when the hidden message is revealed later, allowing further analysis of new messages. b. It's used when a steganography tool and stego-media were used to hide the message content because this method uses a known steganography tool. c. It's used when the cover-media and the stego-media are available for analysis. d. It's used to identify corresponding patterns used in stego-media; this technique creates stego-media and then analyzes them to determine how data is configured in the file